Mirrors/servo
1
0
Fork 0
mirror of https://github.com/servo/servo.git synced 2025-08-03 20:50:07 +01:00
Code Issues Projects Releases Packages Wiki Activity

Store scrolling root scroll offset explicitly

Browse source 
Instead of sneakily setting the content offset and not the transform on
scrolling roots, let scrolling roots specify their scroll offset
directly and separately. This will also be important when adding proper
scrolling support for iframes.
This commit is contained in:
Martin Robinson 2014-09-23 12:58:23 -07:00
parent e9a7b44f68
commit 2724c3c6bb
2 changed files with 23 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

6
components/compositing/compositor_data.rs
View file

@ -18,6 +18,7 @@ use layers::platform::surface::NativeSurfaceMethods;
use servo_msg::compositor_msg::{Epoch, LayerId};
use servo_msg::compositor_msg::ScrollPolicy;
use servo_msg::constellation_msg::PipelineId;
use servo_util::geometry::PagePx;
use std::rc::Rc;
pub struct CompositorData {
@ -39,6 +40,10 @@ pub struct CompositorData {
/// A monotonically increasing counter that keeps track of the current epoch.
/// add_buffer() calls that don't match the current epoch will be ignored.
pub epoch: Epoch,
/// The scroll offset originating from this scrolling root. This allows scrolling roots
/// to track their current scroll position even while their content_offset does not change.
pub scroll_offset: TypedPoint2D<PagePx, f32>,
}
#[deriving(PartialEq, Clone)]
@ -60,6 +65,7 @@ impl CompositorData {
scroll_policy: layer_properties.scroll_policy,
background_color: layer_properties.background_color,
epoch: layer_properties.epoch,
scroll_offset: TypedPoint2D(0., 0.),
};
Rc::new(Layer::new(Rect::from_untyped(&layer_properties.rect),

29
components/compositing/events.rs
View file

@ -56,10 +56,9 @@ pub fn handle_scroll_event(layer: Rc<Layer<CompositorData>>,
}
// Allow children to scroll.
let content_offset_in_page_pixels : TypedPoint2D<PagePx, f32> =
Point2D::from_untyped(&*layer.content_offset.borrow());
let content_offset : TypedPoint2D<DevicePixel, f32> = content_offset_in_page_pixels * scale;
let new_cursor = cursor - content_offset;
let scroll_offset = layer.extra_data.borrow().scroll_offset;
let scroll_offset_in_device_pixels = scroll_offset * scale;
let new_cursor = cursor - scroll_offset_in_device_pixels;
for child in layer.children().iter() {
let child_bounds = child.bounds.borrow();
if child_bounds.contains(&new_cursor) &&
@ -72,8 +71,10 @@ pub fn handle_scroll_event(layer: Rc<Layer<CompositorData>>,
}
}
clamp_scroll_offset_and_scroll_layer(layer, content_offset + delta, window_size, scale)
clamp_scroll_offset_and_scroll_layer(layer,
scroll_offset_in_device_pixels + delta,
window_size,
scale)
}
pub fn clamp_scroll_offset_and_scroll_layer(layer: Rc<Layer<CompositorData>>,
@ -89,15 +90,19 @@ pub fn clamp_scroll_offset_and_scroll_layer(layer: Rc<Layer<CompositorData>>,
Length(new_offset.y.get().clamp(&min_y, &0.0)));
let new_offset_in_page_px = new_offset / scale;
let untyped_new_offset = new_offset_in_page_px.to_untyped();
if *layer.content_offset.borrow() == untyped_new_offset {
if layer.extra_data.borrow().scroll_offset == new_offset_in_page_px {
return false
}
// FIXME: This allows the base layer to record the current content offset without
// updating its transform. This should be replaced with something less strange.
*layer.content_offset.borrow_mut() = untyped_new_offset;
scroll_layer_and_all_child_layers(layer.clone(), new_offset_in_page_px)
// The scroll offset is just a record of the scroll position of this scrolling root,
// but scroll_layer_and_all_child_layers actually moves the child layers.
layer.extra_data.borrow_mut().scroll_offset = new_offset_in_page_px;
let mut result = false;
for child in layer.children().iter() {
result |= scroll_layer_and_all_child_layers(child.clone(), new_offset_in_page_px);
}
return result;
}
fn scroll_layer_and_all_child_layers(layer: Rc<Layer<CompositorData>>,